EP0595727A1 - Improvements to vibration - damping hydraulical supports - Google Patents

Abstract

This is a vibration-damping hydraulic support of the type with axial excursion comprising an axisymmetric rigid base (1), a coaxial annular rigid reinforcing member (6), a first annular elastic wall joining the base to the reinforcing member, a second elastic wall carried by the reinforcing member and delimiting, together with it, the base and the first wall, a leaktight chamber, a partition located inside the chamber so as to divide the latter into two pockets, a restricted passage (19) located in a rigid portion of the partition and causing the two pockets to communicate with each other permanently, and a liquid mass filling the two pockets as well as the restricted passage. At least one tunnel (36) extending in a circular arc-shape centred on the axis of the base is hollowed out from the intermediate partition, of which tunnel the two ends communicate respectively with the two chambers, and a banana-shaped valve (35) is housed in this tunnel so as to able to slide freely in it. <IMAGE>

Description

• une embase rigide centrale de révolution autour d'un axe X,
• une armature rigide annulaire d'axe X,
• une première paroi élastique annulaire reliant l'embase à l'armature,
• une seconde paroi élastique portée par l'armature et délimitant avec elle, l'embase et la première paroi, une chambre étanche,
• une cloison disposée à l'intérieur de la chambre de façon à diviser celle-ci en deux poches,
• un passage étranglé disposé dans une portion rigide de la cloison et faisant communiquer en permanence les deux poches entre elles,
• et une masse liquide remplissant les deux poches ainsi que le passage étranglé.

The invention relates to hydraulic anti-vibration supports of the axial travel type comprising:

• a rigid central base of revolution around an X axis,
• an annular rigid reinforcement of axis X,
• a first annular elastic wall connecting the base to the frame,
• a second elastic wall carried by the frame and delimiting with it the base and the first wall, a sealed chamber,
• a partition arranged inside the chamber so as to divide the latter into two pockets,
• a constricted passage arranged in a rigid portion of the partition and making the two pockets communicate with each other permanently,
• and a liquid mass filling the two pockets as well as the constricted passage.

Such supports are intended to be interposed between two rigid elements, such as for example a vehicle chassis and the engine of this vehicle or a link forming part of a suspension train of said vehicle, in order to dampen the transmission of oscillations. or vibrations from one of these elements to the other.

Their operation is as follows: the application of an oscillation on one of the two parts constituted by the base and the armature relative to the other in the axial direction of these parts has the effect of alternately deforming the two chambers by alternately discharging liquid from one chamber to the other through the constricted passage and, for a predetermined value of the frequency of the oscillations, the volume of liquid present in said constricted passage is subjected to a phenomenon of resonance which has the effect of effectively ensuring the desired amortization.

In improved embodiments of the supports of the type in question, there are also found, carried by the intermediate partition, means suitable for filtering certain vibrations at relatively high frequency, means constituted by a valve mounted across an orifice communicating the two chambers so that they can vibrate.

The vibrations of this valve, often called "high frequency decoupling valve", have the effect of effectively filtering out some of the vibrations of the same frequency generated on the base and / or on the armature, thereby preventing their transmission between these two parts.

In the known embodiments of these decoupling means, the valve generally consists of a plate or membrane trapped between two grids or perforated plates which each delimit a portion of one of the two chambers.

Although some of these embodiments are satisfactory in practice, some others are not entirely satisfactory in the sense that the chronic applications of the valve on the grids which limit its deflections can be a source of unpleasant noises of the kind of clicks. .

The present invention aims, above all, to eliminate this drawback.

To this end, the hydraulic antivibration supports of the kind in question according to the invention are essentially characterized in that they comprise, on the one hand, at least one tunnel hollowed out in a rigid portion of the intermediate partition and extending according to a arc of a circle centered on the axis common to the base to the frame, tunnel whose two ends communicate respectively with the two chambers and, on the other hand, a valve in the shape of a banana housed in this tunnel and able to slide freely angularly along it.

At this point in the description, it should be recalled that it has already been proposed to constitute a "decoupling" valve by at least one cylindrical tile capable of oscillating angularly in a complementary housing.

But in the embodiments proposed (document FR-A-87 11057), the support considered was of a type with diametrical deflections and the displacement of the tiles was carried out according to a plane parallel to the direction of the vibrations to be filtered and not, as in the present case, in a plane perpendicular to the direction of the vibrations to be filtered: this latter conception did not seem natural and therefore achievable with interest before the present invention, contrary to what experience shows.

• le passage étranglé est délimité essentiellement par une rainure s'étendant selon un arc de cercle et réservée entre le clapet et le tunnel,
• le support comprend, d'une part, deux tunnels tels que définis ci-dessus, s'étendant chacun selon un demi-cercle et symétriques l'un de l'autre par rapport à un plan axial et, d'autre part, deux clapets tels que définis ci-dessus logés respectivement dans les deux tunnels,
• le support est d'un type à axe traversant pour lequel l'embase rigide centrale est un tronçon tubulaire interne, l'armature rigide annulaire est un tronçon tubulaire externe entourant le tronçon tubulaire interne, les deux parois élastiques sont des bagues interposées entre les deux tronçons tubulaires, à leurs deux extrémités axiales, et la cloison intermédiaire est une rondelle qui comprend elle-même un anneau élastique et un anneau rigide s'entourant mutuellement,
• le support selon l'alinéa précédent est réalisé conformément aux enseignements du document FR-A-91 13023, selon lesquels, d'une part, les deux bagues élastiques sont interposées radialement entre les deux tronçons tubulaires qu'elle relie entre eux de façon à travailler essentiellement au cisaillement lors des déplacements relatifs axiaux de ces deux tronçons, et d'autre part, ces deux bagues élastiques sont totalement décalées radialement par rapport à l'anneau élastique qui constitue en partie la rondelle intermédiaire, les projections axiales desdites bagues et dudit anneau ne se recouvrant donc pas, même en partie.

In advantageous embodiments, use is also made of one and / or the other of the following arrangements:

• the constricted passage is essentially delimited by a groove extending in an arc of a circle and reserved between the valve and the tunnel,
• the support comprises, on the one hand, two tunnels as defined above, each extending in a semicircle and symmetrical to each other with respect to an axial plane and, on the other hand, two valves as defined above housed respectively in the two tunnels,
• the support is of a traversing axis type for which the central rigid base is an internal tubular section, the annular rigid reinforcement is an external tubular section surrounding the internal tubular section, the two elastic walls are rings interposed between the two tubular sections, at their two axial ends, and the intermediate partition is a washer which itself comprises an elastic ring and a ring rigid surrounding each other,
• the support according to the preceding paragraph is produced in accordance with the teachings of document FR-A-91 13023, according to which, on the one hand, the two elastic rings are interposed radially between the two tubular sections which it connects together so as to work essentially in shearing during the relative axial displacements of these two sections, and on the other hand, these two elastic rings are totally offset radially with respect to the elastic ring which partially constitutes the intermediate washer, the axial projections of said rings and of said ring therefore not overlapping, even in part.

The invention includes, apart from these main provisions, certain other provisions which are preferably used at the same time and which will be more explicitly discussed below.

In what follows, a preferred embodiment of the invention will be described with reference to the accompanying drawing, of course in a non-limiting manner.

Figures 1 and 2, of this drawing, show respectively in axial section along I-I Figure 2 and in cross section along II-II Figure 1, a hydraulic anti-vibration support established according to the invention.

• une armature tubulaire rigide intérieure 1 comprenant un tronçon de tube 2 et trois colliers cylindriques 3, 4 et 5 entourant jointivement ledit tronçon, ces trois colliers étant juxtaposés axialement les uns contre les autres et maintenus ainsi par sertissage vers l'extérieur des extrémités du tronçon de tube,
• une armature tubulaire rigide extérieure 6 comprenant trois colliers cylindriques 7,8 et 9 juxtaposés axialement dont les deux extrêmes 7 et 9 sont prolongés radialement par des collerettes extérieures 10 et 11 et sont emmanchés à force dans respectivement les deux extrémités axiales d'un alésage 12 évidé dans une pièce 13,
• une bague élastique 14 adhérée intérieurement sur le collier 3 et extérieurement sur le collier 7,
• une bague élastique 15 adhérée intérieurement sur le collier 5 et extérieurement sur le collier 9,
• un liquide L remplissant la poche annulaire constituée par l'ensemble des armatures tubulaires rigides 1 et 6 et des bagues 14 et 15,
• et une cloison annulaire intermédiaire 16 immergée dans la poche ci-dessus définie et reliant radialement entre eux de manière étanche les deux colliers 4 et 8 de façon à diviser la poche annulaire en deux chambres annulaires A et B.

Said support has a general shape of revolution around a vertical axis and comprises:

• an inner rigid tubular reinforcement 1 comprising a tube section 2 and three cylindrical collars 3, 4 and 5 contiguously surrounding said section, these three collars being juxtaposed axially against one another and thus held by crimping towards the outside of the ends of the section tube,
• a rigid external tubular frame 6 comprising three cylindrical collars 7,8 and 9 axially juxtaposed, the two ends 7 and 9 of which are extended radially by external flanges 10 and 11 and are force-fitted into the two axial ends respectively of a bore 12 hollowed out in a part 13,
• an elastic ring 14 adhered internally to the collar 3 and externally to the collar 7,
• an elastic ring 15 adhered internally to the collar 5 and externally to the collar 9,
• a liquid L filling the annular pocket formed by all of the rigid tubular frames 1 and 6 and the rings 14 and 15,
• and an intermediate annular partition 16 immersed in the pocket defined above and radially connecting the two collars 4 and 8 radially between them so as to divide the annular pocket into two annular chambers A and B.

• un anneau rigide 17 prolongeant intérieurement le collier 8 et faisant bloc avec lui,
• et un anneau élastique 18 reliant radialement de façon étanche le bord intérieur de l'anneau 17 au collier 4.

The partition 16 itself comprises:

• a rigid ring 17 internally extending the collar 8 and forming a block with it,
• and an elastic ring 18 radially sealingly connecting the inner edge of the ring 17 to the collar 4.

A narrow channel 19 hollowed out in the ring 17 permanently communicates the two pockets A and B.

• des bourrelets annulaires extérieurs rigides radiaux 28,29 faisant corps avec les colliers 3 et 5 et débordant radialement vers l'extérieur jusqu'à une distance, de l'axe X, supérieure au rayon intérieur de l'anneau 16, conformément aux enseignements du document FR-A-91 13023,
• un axe épaulé 30 -représenté en traits mixtes- qui traverse jointivement le tronçon de tube 2 et qui constitue l'un des deux éléments rigides entre lesquels on désire amortir le transfert des vibrations, l'autre élément rigide étant la pièce 13, ces deux éléments 30 et 13 étant eux-mêmes solidarisés de toute façon désirable avec respectivement deux ensembles appropriés tels qu'un châssis de véhicule et que le moteur à combustion interne ou un train de suspension de ce véhicule,
• et des bossages 31 venus de moulage avec les bagues élastiques 14 et 15 et faisant saillie axialement sur des rondelles 32 également venues de moulage avec lesdites bagues et recouvrant les collerettes 10 et 11, lesdites bagues pouvant servir de butées de fin de course axiale en venant en contact avec des portées en regard solidaires de l'élément 30.

We still see in Figure 1:

• radial rigid external annular beads 28, 29 forming a body with the collars 3 and 5 and projecting radially outwards up to a distance, from the X axis, greater than the internal radius of the ring 16, in accordance with the teachings of the document FR-A-91 13023,
• a stepped axis 30 -represented in dashed lines- which crosses contiguously the tube section 2 and which constitutes one of the two rigid elements between which it is desired to dampen the transfer of vibrations, the other rigid element being the part 13, these two elements 30 and 13 being themselves secured in any desirable manner with respectively two appropriate assemblies such as a vehicle chassis and the internal combustion engine or a suspension train of this vehicle,
• and bosses 31 coming from molding with the elastic rings 14 and 15 and projecting axially on washers 32 also coming from molding with said rings and covering the flanges 10 and 11, said rings being able to serve as axial end-of-travel stops coming from in contact with facing bearing surfaces integral with the element 30.

It can also be seen in this FIG. 1 that the beads 28, 29 are themselves coated by annular webs 33, 34 extending radially inward the elastic rings 14 and 15 and coming from molding with the latter.

Means are also provided, called "decoupling" means, to prevent the transmission, from one of the plates 1 and 6 to the other, of certain axial vibrations of relatively high frequency and low amplitude.

These means are of the type known per se comprising a floating valve, two opposite faces of which communicate respectively with the two chambers A and B and whose range of travel is limited.

The valve in question here consists of at least one curved banana-shaped part 35 extending in an arc centered on the axis X and housed contiguously in a tunnel 36 of complementary shape itself hollowed out in the ring rigid 17, so as to be able to slide freely along this tunnel, around the axis X, the two ends of said tunnel opening respectively into the two chambers A and B through suitable mouths of relatively large sections, one of which is visible at 37 in FIGS. 1 and 2.

Each banana 35 is extended at its two ends by narrower legs 38 suitable for abutting at the end of the race against the bottoms opposite the tunnel 36 without the banana obstructing the corresponding mouths 37.

These funds are advantageously upholstered or constituted by a layer of elastomer 39, which eliminates the noises due to the end of travel stops.

In the illustrated embodiment, there is a pair of tunnels 36 each extending on a semicircle and symmetrical to each other with respect to an axial plane of the sleeve, these two tunnels respectively containing two identical bananas 35 .

With such a system, the vibrations of relatively small amplitude and relatively high frequency applied axially between the two frames 1 and 6 result in angular vibrations of the bananas 35 in their tunnels, vibrations which have the effect of filtering the transmission of the axial vibrations ci above between the two frames.

With such an embodiment, it is advantageous to constitute the constricted passage 19 by a groove extending in an arc of a circle and reserved between each banana and the opposite face of the tunnel in which it is housed, this groove being able to be hollowed out in the banana itself, as illustrated, or on the contrary in the opposite wall.

It can also be seen in FIGS. 1 and 2 that all the walls of each tunnel 36, other than that constituting in part the constricted passage, are lined with a layer 40 of elastomer, which can contribute to catching up with the clearances and the silence of the angular sliding of bananas 35 in tunnels 36.

To facilitate the sliding of these bananas, these and / or the facing faces of the tunnel are advantageously coated with a layer of low friction coefficient, for example made of polytetrafluoroethylene (Teflon).

As a result of which, and whatever the embodiment adopted, hydraulic antivibration supports are finally obtained, the constitution, operation and advantages of which result sufficiently from the above.

• celles où les positions relatives intérieure et extérieure des portions rigides et des portions élastiquement déformables comprises par les bagues 14 et 15 et par la rondelle 16 seraient inversées par rapport à celles décrites et illustrées ci-dessus,
• celles où le support considéré serait d'un type à débattements axiaux mais sans "axe traversant", la première armature tubulaire 1 ci-dessus étant alors remplacée par un plot central, l'une des deux bagues élastiques 14 et 15 ci-dessus, par un soufflet flexible non évidé centralement et porté par la seconde armature 2 et le double anneau 17,18 ci-dessus, par une cloison rigide pleine juste évidée par le (ou les) tunnel(s) 36,
• et celles où le support considéré comprendrait encore deux clapets ou bananes comme dans le mode de réalisation ci-dessus décrit et illustré, mais où ces deux bananes et/ou leurs logements en tunnel seraient différents, les courses des débattements des deux bananes étant par exemple différentes et/ou les sections des deux gorges constituant les passages étranglés, ce qui permettrait de "caler" les deux bananes sur deux fréquences différentes et/ou deux amplitudes différentes des oscillations à amortir.

As goes without saying, and as it already follows from the above, the invention is in no way limited to those of its modes of application and embodiments which have been more especially envisaged; on the contrary, it embraces all variants, in particular:

• those where the relative interior and exterior positions of the rigid portions and of the elastically deformable portions comprised by the rings 14 and 15 and by the washer 16 would be reversed with respect to those described and illustrated above,
• those where the support considered would be of a type with axial deflections but without "through axis", the first tubular frame 1 above then being replaced by a central stud, one of the two elastic rings 14 and 15 above, by a flexible bellows not hollowed out centrally and carried by the second frame 2 and the double ring 17.18 above, by a rigid rigid partition just hollowed out by the tunnel (s) 36,
• and those where the support considered would still include two valves or bananas as in the embodiment described and illustrated above, but where these two bananas and / or their housing in the tunnel would be different, the travel of travel of the two bananas being for example different and / or the sections of the two grooves constituting the strangled passages, which would make it possible to "wedge" the two bananas on two different frequencies and / or two different amplitudes of the oscillations to be damped.

Claims (8)

Hydraulic antivibration support of the axial deflection type comprising a rigid central base (1) of revolution about an X axis, a rigid annular frame (6) of X axis, a first annular elastic wall (14) connecting the base to the frame, a second elastic wall (15) carried by the frame and delimiting with it, the base and the first wall, a sealed chamber, a partition (16) arranged inside the chamber so as to divide the latter in two pockets (A, B), a constricted passage (19) arranged in a rigid portion of the partition and causing the two pockets to communicate with each other permanently, and a liquid mass filling the two pockets as well as the constricted passage , characterized in that it comprises, on the one hand, at least one tunnel (36) hollowed out in a rigid portion of the intermediate partition (16) and extending in an arc centered on the X axis, tunnel the two ends of which communicate respectively with the two chambers (A, B) and, on the other hand, a valve (35) in the form of a banana housed in this tunnel and which can slide freely angularly along the latter. Support according to claim 1, characterized in that the constricted passage (19) is defined essentially by a groove extending in an arc of a circle and reserved between the valve (35) and the tunnel (36). Support according to any one of the preceding claims, characterized in that it comprises, on the one hand, two tunnels (36) as defined above, each extending in a semicircle and symmetrical one of the other with respect to an axial plane and, on the other hand, two valves (35) as defined above housed respectively in the two tunnels. Support according to any one of claims 1 and 2, characterized in that it comprises, on the one hand, two tunnels (36) as defined above and, on the other hand, two valves (35) as defined above housed respectively in the two tunnels, some of the comparable dimensions of these two tunnels and / or these two valves being different. Support according to any one of the preceding claims, characterized in that it is of a type with through axis for which the central rigid base (1) is an internal tubular section, the annular rigid reinforcement (2) is a outer tubular section surrounding the inner tubular section, the two elastic walls (14,15) are rings interposed between the two tubular sections, at their two axial ends, and the intermediate partition (16) is a washer which itself comprises a elastic ring (18) and a rigid ring (17) surrounding each other. Support according to claim 5, characterized in that, on the one hand, the two elastic rings (14,15) are interposed radially between the two tubular sections (1,2) which it connects together so as to work essentially at shear during the relative axial displacements of these two sections, and in that, on the other hand, these two elastic rings are totally offset radially with respect to the elastic ring (18) which partly constitutes the intermediate washer, the axial projections of said rings and said ring therefore not overlapping, even in part. Support according to any one of the preceding claims, characterized in that the walls of the tunnel (36), other than that constituting in part the constricted passage, are covered with a layer (40) of elastomer. Support according to any one of the preceding claims, characterized in that the valve (35) and / or the opposite faces of the tunnel (36) are coated with a layer with a low coefficient of friction.

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